The present invention relates to ceramic matrix composites and more particularly, although not exclusively, to products formed from such composites by sintering.
Ceramic Matrix Composites (CMC) are often used, for example in aerospace applications, where components are required to withstand high temperatures. For many such CMC components, a woven fabric comprising ceramic fibres is typically provided as a generally two-dimensional sheet or layer. A plurality of such layers are stacked within the final component.
For sintered CMCs, a matrix material binds the layered fibre structure both during forming and also after sintering. In forming a desired product, the woven material is doused in the matrix material and successive layers are built up to the desired depth. Depending on the form of the product to be produced, the layers may be laid flat or applied over a male or female mould such that the layers are generally parallel with the contour of the outer surface of the product.
The make-up of the matrix material and woven fabric as well as variations in the applied pressure and temperature to sinter the structure can be used to generate the desired mechanical properties of the end product. In this manner it is possible to achieve varying levels of fibre volume fraction and matrix densification in the final product, which impacts, for example, on tensile strength, bending strength and damage tolerance.